The problem is that audio relies on the DCE rpcd, which doesn't start if
there's no network.  Consequently, the audio server (Aserver) fails to
start either.

You can always access /dev/audio directly, but you won't be able to
use HP's audio software, such as the Audio Control Panel or the Audio
Editor.  Furthermore, this method is not documented by HP.

To get Aserver to work, you basically have to make the machine believe
it's on a network.  You have to get the lan interface up; loopback is
not enough.  Plugging a transceiver into the AUI port is reported to
work on 715s and 712s.

Another solution is to restore /usr/audio/*, llbd and libAt.* from a
9.x backup tape and replace rpcd with a symbolic link to llbd.  Then,
you can use audio in much the same way as on HP-UX 9.x.  The only
problem is that the buttons in the audio_editor don't have any text in
them, so one has to guess which one does what.

Unfortunately, SD-UX doesn't work with this configuration, which makes it
impossible to install or remove SD packages.  To fix this, you have to
recreate the standard RPC symlinks - link /usr/bin/rpcd to
/opt/dce/sbin/rpcd,
and /opt/dce/sbin/rpcd to dced.